Field of the Invention
The present invention relates to a light control device and a transparent display apparatus.
Discussion of the Related Art
Recently, as society advances to the information-oriented society, the display field of processing and displaying a massive amount of information is rapidly advancing, and correspondingly, various flat panel display (FPD) apparatuses have been developed and are attracting much attention. Examples of the FPD apparatuses include LCD apparatuses, plasma display panel (PDP) apparatuses, field emission display (FED) apparatuses, electroluminescence display (ELD) apparatuses, organic light emitting diode (OLED) display apparatuses, etc.
Recently, FPD apparatuses have become thin and light, and are low in consumption power, and thus, the application field of display apparatuses is continuously increasing. Particularly, a display apparatus is used as a user interface in most electronic devices, mobile devices, etc.
Moreover, transparent display apparatuses which enable a user to see a background or an object disposed on a rear surface thereof are being actively researched recently. The transparent display apparatuses are good in space availability, interior, and design and may be applied to various fields. The transparent display apparatuses realize an information recognition function, an information processing function, and an information display function by using a transparent electronic device, thereby solving the spatial limitation and visual limitation of electronic devices. For example, a transparent display apparatus may be applied to windows of buildings or vehicles and thus may be implemented as a smart window which allows a background to be seen or displays an image.
The transparent display apparatuses may be implemented as organic light emitting display apparatuses. In this case, power consumption is low, a contrast ratio is reduced in an environment having light although a contrast ratio is not changed in a dark environment. The contrast ratio in the dark environment may be defined as a dark room contrast ratio, and the contrast ratio in the environment having light may be defined as a bright room contrast ratio. The transparent display apparatuses include a transmissive area for enabling a user to see a background or an object disposed on a rear surface thereof, and for this reason, the dark room contrast ratio is reduced. Therefore, when a transparent display apparatus is implemented as an organic light emitting display apparatus, the transparent display apparatus may include a light control device for realizing a light shield mode, where light is blocked for preventing the dark room contrast ratio from being reduced, and a transmissive mode where light is transmitted.
The light control device may include a first substrate, a second substrate, a first electrode disposed on the first substrate, a second electrode disposed on the second substrate, a liquid crystal layer that transmits or blocks light by using dichroic dyes and liquid crystal disposed between the first electrode and the second electrode, and a plurality of partition walls for maintaining a constant gap of the liquid crystal layer. Recently, due to the area enlargement of display apparatuses, the transparent display apparatuses are manufactured to have a large area. In this case, the light control device is manufactured to have a large area, and for this reason, the liquid crystal and dichroic dyes of the liquid crystal layer included in the light control device can be partially distributed on one side due to a gravity defect. For this reason, the liquid crystal and the dichroic dyes are non-uniformly distributed in the liquid crystal layer of the light control device, and consequently, a light shield transmittance increases in the light shield mode, whereby a light shield rate is reduced in a portion of the liquid crystal layer.